2. Is radiation our daily helper or our

Is radiation our daily helper or our enemy?

Today, knowledge of radioactive substances and radiation helps people in various fields of science and technology, but the vast majority of people are frightened by the word "radiation". All because the world remembered it with the greatest planetary tragedies - Chernobyl and Fukushima.

Scientifically, radiation is a type of radiation that changes the state of nuclei or atoms, converting them into electrically charged ions and products of nuclear reactions. It is divided into specific types that have different penetrating power and different effects on the human body.

Alpha radiation is a stream of positively charged particles (nuclei of helium atoms) moving at a speed of about 20,000 km/sec. A sheet of paper absorbs alpha radiation, and it almost does not penetrate the human skin. But it is dangerous if the particles get into the body with food, air or through wounds.

Beta radiation is the flow of negatively charged particles (electrons). Their speed is close to the speed of light. Beta radiation can penetrate body tissues to a depth of one or two centimetres. Ordinary clothing is a protection against this.

Gamma radiation is short-wave electromagnetic radiation. In terms of properties, it is close to X-ray but endowed with much greater speed and energy and propagates at the speed of light. Gamma radiation has high penetrating power, so it is weakened by the walls of houses, metal structures.

Use of radiation:

Like most things and phenomena around us, the effects of radiation can be beneficial, harmful or almost invisible to the body. In practice, sources of ionizing radiation are used in medicine during X-ray and fluorographic examinations, study and verification of the endocrine system, treatment of cancer. Knowledge of radioactivity is used as a basis for dating methods in archaeology and palaeontology to determine the exact age of the find when inspecting people and luggage at airports, sterilizing medical instruments and food, and operating various sensors and meters for high-precision measurements in science and technology.

However, to assess the impact of radiation on nature and man, let us turn to the events of April 1986 - the Chernobyl accident.

On April 26, 1986, the most significant accident in the industry's history occurred, which was accompanied by the release of radioactive substances into the environment. Twenty-three radionuclides were released in the emissions, which rose with the air current to a height of 1200 m.

The main radioactive substances released into the atmosphere were uranium-238, plutonium-239, iodine-131, cesium-134, cesium-137 and strontium-90.

Cesium-137 is the most biologically dangerous isotope, which accounts for up to 90% of the external radiation dose of personnel (half-life - about 30 years). It gets into the human body with food. The highest concentrations of cesium-137 are found in the surface layer of the soil, from where it enters plants and fungi. Caesium is an ionic competitor to potassium, i.e. in living organisms, it can replace potassium and spread throughout the body. To avoid this, you should eat foods rich in potassium (apricots, green peas, potatoes, tomatoes, melons).

Strontium-90 - has significant mobility in ecosystems, is effectively integrated into the chain "soil-plant-animal-precipitation-soil", water-soluble - is a substantial component of the flow of radioactive substances entering the zone by water (half-life - about 29 years). Strontium-90 is an "ionic competitor" of calcium, which is part of the bones involved in blood clotting. Causes sarcoma. To prevent the displacement of calcium by strontium in metabolic processes in the body, you need to use drugs containing calcium or condensed milk, cheese, eggs, citrus fruits, zucchini, cherries, etc.

Plutonium (isotopes 238, 239, 240) - poses a significant danger to the human body due to alpha radiation and chemical toxicity but does not have substantial environmental and biological mobility. The half-life of Pu-239 is about 24 thousand years. Isotopes of this element will determine the radiation situation in the area in the long run.

The behaviour of plutonium in the human body is similar in properties to the conduct of ferric iron. Penetrating the circulatory system, Ru is concentrated in organs and tissues containing elevated concentrations of iron: bone marrow, liver, spleen. The body perceives plutonium as iron: the transferrin protein absorbs plutonium instead of iron, resulting in impaired oxygen transfer. Microphages stretch the element № 94 through the lymph nodes. Plutonium is excreted from the body for a very long time - it takes about 50 years to eliminate 80% of Ru. In the bone marrow of tubular and flat bones, there are almost no hematopoietic cells by the end of the first week. In the liver, there is progressive atrophy of parenchymal cells, foci of necrosis. The genitals are affected. Once in the lungs, even in minimal concentrations, it can cause cancer. Radioactive isotopes of plutonium will persist in the soil for thousands of years.

Iodine-131. The dose of radiation created by it and causing cancer is observed in the thyroid gland in humans. To minimize the accumulation of radioactive iodine in the body during radioactive contamination of the environment, take drugs that saturate the metabolism with ordinary stable iodine — for example, the drug Potassium iodide. When taking potassium iodide simultaneously with the receipt of radioactive iodine, the protective effect is about 97%; when taken 12 and 24 hours before contact with radioactive contamination - 90% and 70%, respectively, when taken 1 and 3 hours after contact - 85% and 50%, more than 6 hours - the effect is negligible.

Americium-241 is the decay product of Pu-241. The only accidental radionuclide whose activity is currently increasing (half-life is 433 years).

Krypton-85. Radiation exposure to humans is mainly due to irradiation of the skin.

How does radiation affect the body?

Humans do not feel the effect of ionizing radiation on the body. Humans do not have a sense organ that would perceive ionizing radiation.

However, the first mechanism of interaction of ionizing radiation with the body is described in two words: radiolysis of water or, more simply, the decay of molecules. The body consists of more than three-quarters of this fluid, so its destruction leads to disaster. Radiolysis produces both free radicals and various neutral compounds is poorly predictable proportions. This is a cascade of pathological reactions: they develop like an avalanche, creating more and more "rolls" that injure the body.

The second mechanism is the direct effect of radiation on chemical bonds in the primary molecules of the body. Nucleic acids (DNA and RNA) are mainly affected. Essential enzymes containing sulfhydryl group-SH, such as adenosine triphosphatase, succinoxidase, hexokinase, carboxylase, cholinesterase, cease to function. However, the same violations occur under the influence of an avalanche of free radicals that appeared during the operation of the first mechanism.

The life of the cell falls into chaos. The processes of biosynthesis and energy metabolism begin to fail or stop altogether, and large-scale defects in DNA that intracellular "self-repair" systems cannot eliminate result in the activation of self-destruction mechanisms.

The consequence of the action of ionizing radiation can be represented in the following order: changes in somatic cells that lead to malignant tumours (more often occur at high doses of radiation); genetic mutations that affect future generations (depending on the dose and dose rate); effects on the fetus and fetus, due to irradiation of the mother during pregnancy; or death at the time of irradiation.

There is an acute radiation sickness at the short-term influence of X-ray, γ or neutron irradiation in a dose not less than 1 Gy (100 rads). During the Chernobyl accident, this diagnosis was confirmed in 134 cases.

In the case of intense radiation, the human body does not have time to create antibodies needed to fight foreign proteins and develops a disease called leukaemia - a tumour of the blood.

Organs and tissues of a person in which radionuclides are concentrated when entering the body from the outside due to genetically determined biochemical processes are called critical organs. Critical organs for various nuclides are: thyroid gland - iodine radionuclides; liver - cesium-137, plutonium -239, gonads - cesium-137, plutonium-239, lungs - krypton-85, plutonium -239, kidneys - cesium-137, bone tissue - strontium-90, plutonium-239, heart - cesium-137

How to protect yourself from ionizing radiation?

In general, radiation protection is possible in three main areas: distance protection, screen protection (for different types of radiation other - from lead plates to a sheet of paper) and reducing the time of contact with radiation. Drug protection and drugs that can protect against radiation began to be actively developed only in the middle of the XX century. Some "donor substances" of SH groups, such as cystamine and cysteamine, proved to be more or less effective and suitable for mass use. It is in the form of tablets in a military individual first aid kit as a radioprotective agent.

However, this algorithm can save your life from radiation:

In the event of a sudden radiation hazard, you should immediately take shelter in the house. The walls of a wooden house attenuate ionizing radiation two times, brick - 10 times; recessed shelters (basements): with a covering from a tree in 7 times, with a cover from a brick or concrete - in 40-100 times;

We do not advise you to panic. Just listen to the announcements of the authorities in emergencies. Reduce the possibility of radiation entering the room - close all windows and doors. Carry out iodine prophylaxis. Aqueous-alcoholic solution of iodine is taken after meals three times a day for seven days for 3-5 drops in a glass of milk or water. It is also recommended to apply iodine tincture in the form of a grid once a day for seven days on the surface of the extremities.

Before entering the room, wash your shoes with water or wipe with a damp cloth, clean clothes with a wet brush and pack tightly in a plastic bag. The person himself needs to take a shower and strictly follow the rules of personal hygiene.

Wet cleaning should be done daily in all rooms, preferably with detergents. You can eat only indoors, wash your hands thoroughly with soap before eating and rinse your mouth with a 0.5 percent solution of baking soda. Use water only from proven sources and food - purchased through the retail network. Agricultural products of individual farms, especially milk, greens, vegetables, and fruits, should be eaten only on health authorities' recommendation.

Limit your stay in the open as much as possible. When leaving the room, it would help if you used handy personal protective equipment (respirator, bandage, raincoat, rubber boots). It is forbidden to undress, sit on the ground, eat or drink while in the open.

It is forbidden to swim in open water until the degree of their radioactive contamination is checked. It is prohibited to collect berries, mushrooms and flowers in the forest.

Wait for information about the place of evacuation. Warn your neighbours, help children, the disabled and the elderly. They must be evacuated first. Collect documents, valuables, medicines, products, a supply of drinking water, the simplest means of sanitation and other things you need in an airtight suitcase; Before leaving the house, turn off the sources of electricity, water and gas, take the prepared stuff, put on a gas mask, respirator or cotton gauze bandage, outerwear, rubber boots.